Improved UnknownSubcommandException, added StringUtils.levenshteinNearest utility method.

Author: prokopyl

src/main/java/fr/zcraft/quartzlib/components/commands/exceptions/UnknownSubcommandException.java

@@ -6,6 +6,8 @@
 import fr.zcraft.quartzlib.components.rawtext.RawText;
 import fr.zcraft.quartzlib.components.rawtext.RawTextPart;
 import fr.zcraft.quartzlib.tools.text.StringUtils;
+import java.util.List;
+import java.util.stream.Collectors;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
 import org.jetbrains.annotations.Nullable;
@@ -33,10 +35,14 @@ public RawText display(CommandSender sender) {
 
         if (nearest != null) {
             text = text.then("\n" + CHAT_PREFIX).color(ChatColor.AQUA)
-                    .then("  " + I.t("Did you mean") + ": ").color(ChatColor.GRAY)
+                    .then("  " + I.t("Did you mean: ")).color(ChatColor.GRAY)
                     .then("/").color(ChatColor.WHITE)
-                    .then(getParents() + " ").color(ChatColor.AQUA)
-                    .then(nearest).color(ChatColor.DARK_AQUA);
+                    .then(getParents() + " ").style(ChatColor.AQUA, ChatColor.UNDERLINE)
+                        .hover(I.t("Click to insert this command"))
+                        .suggest("/" + getParents() + " " + nearest)
+                    .then(nearest).style(ChatColor.DARK_AQUA, ChatColor.UNDERLINE)
+                        .hover(I.t("Click to insert this command"))
+                        .suggest("/" + getParents() + " " + nearest);
         }
 
         return text.build();
@@ -46,20 +52,12 @@ public RawText display(CommandSender sender) {
 
     @Nullable
     private String getNearestCommand() {
-        String nearest = null;
-        int nearestDistance = MAX_DISTANCE;
+        List<String> names = commandGroup.getSubCommands()
+                .stream()
+                .map(CommandNode::getName)
+                .collect(Collectors.toList());
 
-        for (CommandNode subCommand : commandGroup.getSubCommands()) {
-            String name = subCommand.getName();
-            int distance = StringUtils.levenshteinDistance(attemptedSubcommand, name);
-
-            if (distance < nearestDistance) {
-                nearest = name;
-                nearestDistance = distance;
-            }
-        }
-
-        return nearest;
+        return StringUtils.levenshteinNearest(attemptedSubcommand, names, MAX_DISTANCE);
     }
 
     private String getParents() {

src/main/java/fr/zcraft/quartzlib/tools/text/StringUtils.java

@@ -1,12 +1,41 @@
 package fr.zcraft.quartzlib.tools.text;
 
+import org.jetbrains.annotations.Nullable;
+
 /**
  * Various string-related utilities.
  */
 public final class StringUtils {
     private StringUtils() {
     }
 
+    /**
+     * Find the nearest from a given string among the given list of candidates,
+     *   computed based on a Levenshtein Distance.
+     * <p>The string must be from at most a given maximum distance of all candidates, else null is returned.</p>
+     * @param toTest The string to test.
+     * @param candidates The list of candidates.
+     * @param maxDistance The maximum distance.
+     * @param <T> The type of CharSequence to test (usually String)
+     * @return The nearest candidate to the string to test, if found within maxDistance.
+     */
+    @Nullable
+    public static <T extends CharSequence> T levenshteinNearest(T toTest, Iterable<T> candidates, int maxDistance) {
+        T nearest = null;
+        int nearestDistance = maxDistance;
+
+        for (T subCommand : candidates) {
+            int distance = StringUtils.levenshteinDistance(toTest, subCommand);
+
+            if (distance < nearestDistance) {
+                nearest = subCommand;
+                nearestDistance = distance;
+            }
+        }
+
+        return nearest;
+    }
+
     /**
      * Compute the distance of Levenshtein Distance between two strings.
      *